1. Field of the Invention
The present invention relates to a method for manufacturing a susceptor that holds a semiconductor wafer, for example, used in performing film formation on the semiconductor wafer.
2. Description of the Related Art
Generally, a CVD (Chemical Vapor Deposition) apparatus is used in forming an epitaxial film or the like on a wafer in a semiconductor manufacturing process. In such a CVD apparatus, a wafer is placed on a susceptor made of SiC or the like and a uniform process gas is supplied to the wafer from above while the wafer is being heated and rotated to form an epitaxial film on the wafer, as described, for example, in Japanese Patent Application Laid-Open No. 11-67675.
In recent years, with developments for higher speed and higher withstand voltage in a power semiconductor device such as a power MOSFET or IGBT (insulated gate bipolar transistor), an epitaxial film formed on a wafer is required to grow as thick as tens to hundreds of micrometers.
However, when a wafer is heated and a process gas is supplied thereto from above as described above, a coating is also formed on members other than on the wafer, which causes the wafer to be stuck on a susceptor. Then, the wafer fractures and particles are produced therefrom, resulting in low yield and reliability.
Accordingly, for example, embossing a surface of the susceptor may be proposed to prevent a wafer from being stuck on the susceptor. However, it is difficult to prevent the wafer from being stuck on the susceptor by only the embossing work because rough surface portions will be completely buried due to thick film growth as thick as 100 μm. Accordingly, it will be required to form a highly rough surface; however, there is a problem that it is difficult to finely machine a surface of a rigid material such as SiC and further control the shape thereof to be spherical.